Genius Scan Enterprise is the most powerful paper document scanner app for Android. It allows you to scan all kinds of paper documents from receipts to invoices to business cards to photos. And then, you can save them in a database or email them or even print them.

The best part of this app is that it works as a true scanner. That means you can take a picture of a document and it will automatically remove the background and clean it so you can read the text clearly.

With this, you can also merge the documents you scan into a PDF file.